Inert matrix fuel deployment for reducing the plutonium the stockpile in reactors.

1. Inert matrix fuel deployment for reducing the plutonium the stockpile in reactors. Claude Degueldre Engineering Department, Lancaster University, Lancaster, UK SBNWM #MRS 2017 @ 29 Oct - 03 Nov 2017.

2. IMF Goal and Objective • Desired goal: eliminate plutonium and minor actinides excesses • Desired objective: use them to produce energy in reactors • Opt for an economical ecological safe and sustainable solution economical ecological safe sustainable

3. Concept for Pu-IMF utilization in LWR (last cycle)

4. Properties of a fuel

5. Examples of Inert Matrices

6. Examples of Inert Matrix design and additives

7. . The three levels for IMF utilization in light-water reactors considering homogeneous vs. heterogeneous systems at the fuel, assembly, and core levels. The fuel is either a solid solution ceramic homogeneously doped with plutonium (red) or heterogeneously doped with some uranium (green), or is a composite material with particulates or microspheres (again plutonium-doped red, uranium-doped green) imbedded in inert matrix material. The fuel assemblies themselves may be homogeneous (all fuel rods in a given assembly contain IMF, red) or heterogeneous (red IMF rods distributed among green UO2 fuel—e.g. the French Advanced Plutonium Assembly (APA) concept). The reactor core may also be loaded homogeneously (with red IMF assemblies), or the UO2 core may be partially loaded with some IMF assemblies forming a heterogeneous core loading.

8. R&D work required • Material testing • Neutronics optimisation • System studies homogeneity vs. heterogeneity for: fuel material and fissile at the FUEL ASSEMBLY CORE level • Inventory after high burn-up • Dispositions: multirecycling leaching solubility oronce-through with low solubility for geodisposal

9. Zirconia IMF concept • With IMF no new Pu is produced (contrary to MOX) • (Er,Y,Pu,Zr)O2-x solid solution with fissile & burnable poison. • The plutonium in spent IMF foreseen for disposal is devaluated. • For the material qualification, the relevant fuel properties are: - fissile and component densities, - porosity, micro/nano structural studies, - thermal conductivity, - stability under irradiation, - efficient retention of fission products and - solubility: a key property for the disposal of the spent fuel.

10. Cooperative work • Basic neutronic properties calculations • Comparison code and library • Neutron physics benchmark: progress & <2% consistency for Er2O3-PuO2-ZrO2 • Ref. proceedings of IMF3, ENEA 1997

11. 6th IMF workshop, 30 May-2 Jun. 2000 # EMRS • Introducing new inert matrices • Material testing in research reactors • Neutronics calculation for LWR • Dispositions • Prog. Nucl. Energy 38 (2001)

12. IMF R&D work in Switzerland • At PSI: IMF since 1995 • ZrO2 & ZrN material preparation and testing • Neutronics calculation for LWR • Disposition • Organising IMF workshops COOPERATION PSI, EPFL, ETHZ Uni Geneva Fabrication of Inert-Matrix-Fuel (IMF) for plutonium incineration; irradiation tests in the Halden Research Reactor(N)

13. (Er,Y,Am,Pu,Zr)O2-x IMF density/porosity • Ceramography • X-ray Tomo • ND • XRD • IMF data: Density Porosity Fissile density Thermal conductivity

14. ZrO2 IMF R&D work in Switzerland • Integral measurements with a plutonium inert matrix fuel rod in a heterogeneous light water reactor lattice • Sectional view of a SVEA-96 BWR fuel assembly indicating the voided moderator conditions simulated in LWR-PROTEUS Core 3A • No major uncertainties in pin power distribution predictions, neither for the MOX nor for the Pu-Er-Zr oxide IMF investigated • ○UO2● Mesur. •  g scan  BPd pin

15. Neutron radiography of two IMF segments during the OTTO experiment IMF composition: (Er,Y,Am,Pu,Zr)O2-x Capsule 1 and (Y,Am,Pu,U,Zr)O2-x Capsule 2. Pellet diameter 8.00 mm, stack length 67.0 and 67.7 mm, density of plutonium fissile at beginning of life: 0.37 and 0.34 g cm-3, density 5.80 and 6.02 g cm-3 respectively. This image was obtained after one cycle.

16. Central fuel temperature of IMF&MOX @ Halden RP

17. Plutonium inventory as a function of IMF irradiation time in PWR

21. IMF in HTR • The three levels for IMF utilization in high temperature reactors considering homogeneous vs. heterogeneous systems at the • fuel, • assembly, and • core levels.

22. Solubility Zirconia solubility: <10-10 M for pH 3.0 - 8.5 Data from: ■ Kovalenko et al., Russ. J. Inorg. Chem. 6 (1961) 272. ● Adair et al., Ceram. Trans 1 (1987) 135. ▼ Pouchon et al., Progr. Nucl. Energy 38 (2001) 443. ▲ Egberg et al., J. Sol. Chem., 133 (2004) 47. ♦ Michel, 2005 These University of Nantes, (2005).

23. Solubility Glass 10-3 M Sapphire 10-7 M Zirconia 10-10 M

24. R&D for spent zirconia IMF disposition • Zirconia IMF as a Nonproliferation barrier • Material doped with fissile and low solubility or leaching rate

25. SEM comparison of secondary (a,c) and back scattered (b,d) electron images [Lumpkin, 1999]. Conditions: intergrowth between uranpyrochlore and baddeleyite from Jacupiranga carbonatite complex, Brazil. General features and microfracturing, alteration in the uranpyrochlore (lighter gray, (U,Ca,Ce)2(Nb.Ta)2O6(OH,F)) and the baddeleyite (darker gray, ZrO2) 500 & 200 mm width.

26. Very high resistance to proliferation risks • Low leaching potential in acids (HNO3 or HF) even under pressure and elevated temperature or with mixtures of acids. • High mechanical resistance(crushing larger amounts of (Y,Zr)O2-x for dissolution is very difficult).

27. Status of the IMF initiative in 2006 1995 - 200612 Meetings : CH3, It, Fr, EC2, Nl, Jp, UK, US 410 Participants, 15 countries (Aus, B, Cd, CH, Cz, D, Fr, I, In, Is, Jp, Kr, Nl, Ru, S, UK, US), and 3 internationalorganisations(EC, IAEA, OECD) Universities: Michigan, POLIMI, Aachen, Ben Gourion, Delft,Geneva, Lausanne, New Mexico, Ontario, Osaka, Paris, Purdue, Darmstadt. Nat. Lab. : AECL, ANSTO, CEA, CNRS, ENEA, ITU, JAERI, KAERI, IPPE, FZJ, LANL, NRG,ORNL, PNNL, PSI, VNIINM, ….. Industry: BNFL, COGEMA, FRAMATOME-ANP, NRG, SKODA, 86 Papers published in: J. Nucl. Mater. (1999, 2003 & 2006) Prog. Nucl. Energy (2001). 120 Communications : 6 internal reports (ENEA,CEA,NRG,BNFL)

28. IMF programs and perspectives AfterIMF 11 Oct. 2006 @ INL

29. MgOIMF programs and perspectives Results gained from MgO IMF programs: • K. Holliday, Th. Hartmann, F. Poineau, J. R. Kennedy, K. Czerwinski Synthesis and characterization of zirconia–magnesia inertmatrixfuel: Uranium homolog studies, Journal of Nuclear Materials, 393 (2009) 224-229 • K. Holliday, Th. Hartmann, S. R. Mulcahy, K. Czerwinski, Synthesis and characterization of zirconia–magnesia inertmatrixfuel: Plutonium studies, Journal of Nuclear Materials, 402 (2010) 81-86 • S. Miwa, M Osaka, Oxidation and reduction behaviors of a prototypic MgO-PuO2-x inert matrix fuel, Journal of Nuclear Materials, 487 (2017) 1-4. IMF but not for the last cycle

30. MgOIMF programs and perspectives Results gained from the MgO IMF programs: • MgO IMF concept & optimised utilization conditions for utilisation • Excellent neutronic, thermal-conductivity • MgO IMF may be fabricated and used in reactor • Spent fuel dispositionsare evaluated and selected Once through then geodisposal (very low solubility) • A basis of knowledge on MgO inert matrix fuels is being established to allow potential deployment in reactors

31. SiCIMF programs and perspectives Results gained from SiC IMF programs: • R.A. Verrall, M.D. Vlajic, V.D. Krstic, Silicon carbide as an inert-matrix for a thermal reactor fuel, Journal of Nuclear Materials, 274 (1999) 54-60 • D. Pavlyuchkov, R.H. Baney, J.S. Tulenko, H.J. Seifert, Fabrication of particle dispersed inert matrix fuel based on liquid phase sintered SiC, Journal of Nuclear Materials, 415 (2011) 139-146 • K.A. Terrani, J.O. Kiggans, C.M. Silva, C. Shih, L.L. Snead, Progress on matrix SiC processing and properties for fully ceramic microencapsulated fuel form, Journal of Nuclear Materials, 457 (2015) 9-17

32. SiCIMF programs and perspectives Results gained from the SiC IMF programs : • Concepts & optimised conditions for IMF utilisation • Excellent neutronic, thermal-conductivity • SiC IMF may be fabricated and used in reactor • Spent fuel dispositionsare evaluated and selected Once through then geodisposal (non soluble mater) • A basis of knowledge on SiC inert matrix fuels will be established to allow deployment in reactor

33. SiCIMF programs and perspectives Results gained from the SiC IMF programs: • K.H. Sarma, J. Fourcade, S-G. Lee, A.A. Solomon, New processing methods to produce silicon carbide and beryllium oxide inertmatrix and enhanced thermal conductivity oxide fuels, Journal of Nuclear Materials, 352 (2006) 324-333, • Ting Cheng, R. H. Baney, J. Tulenko, The effects of oxygen, carbon dioxide and water vapor on reprocessing silicon carbide inertmatrixfuels by corrosion in molten potassium carbonate, Journal of Nuclear Materials, 411 (2011) 126-130, • J. Braun, Ch. Guéneau, Th. Alpettaz, C. Sauder, F. Balbaud-Célérier,Chemical compatibility between UO2fuel and SiC cladding for LWRs. Application to ATF (Accident-Tolerant Fuels), Journal of Nuclear Materials, 487 (2017) 380-395,

34. IMF programs and perspectives IMF may be part of the clean energy target:

35. Today‘sIMF programs and perspectives Results gained from the IMF programs : • Concepts & optimised conditions for IMF utilisation • Possible IMF solutions, together with their scope (cycle length, safety parameters, etc.) has been defined • Zirconia IMF may be fabricated and used in reactor burning Pu excesses and/or minor actinides • Spent fuel dispositionsare evaluated and optimised for a last cycle followed by geodisposal • A basis of knowledge on ZrO2 inert matrix fuels has been established to test deployment in NPP Nuclear materials @IUMRS May 2019, Nice, Fr.

36. Interest for Nuclear Material Analysis +